Two of the leading competitors for your astro-dollar!. (Photo by Author).

If you’ re like us, the modern electronic era has seen our magazine subscriptions dwindle over the last decade. Gone are the piles of magazines threatening to take over our attic or garage, as we consume more and more of our information digitally. No field changes quicker than astronomy, and up to the minute info is what we all seek on the new comet or solar flare activity that may or may not be eminent. But is there still room for astronomy magazines in our ever-dwindling astro-budget? [Read more...]

Few inventions are as near and dear to our hearts as that of the telescope. Before its invention, astronomy was scarcely better than its pseudo-science companion of astrology in its knowledge of predicting the universe as it truly is. In this week’s review, we’ll look at The Telescopeby Geoff Anderson out from Princeton Press as it traces the history of this noble instrument, its origins, the theory of optics, and our present day understandings and the exciting realm of telescopes yet to come.Out from Princeton University Press!

Think you know everything about telescopes? The Telescope will take you through designs from classical refractors to Coudè focus complexities. This would serve as a good 101 for anyone thinking of building or even purchasing a telescope, as a lot of the optical basics are discussed. You can even skip through chapters, and the author even suggests that you don’t have to struggle through chapters on interferometry (but of course we did!) unless you really want to.

The study of how early astronomers actually functioned always personally fascinates me. We all know the discoveries of Galileo, but just how did he make those refractors in a renaissance era work shop? The absurdity of some of the focal lengths used was astounding; this was required to overcome the fringes on chromatic aberration until 2-element crown and flint objectives were perfected. And don’t forget, they had to handcraft eye-pieces, as well. Just how many modern day telescope makers do that?

The evolution of site selection and observatory construction is also discussed; it’s a generally underappreciated fact that seeing and turbulence makes up about 90% of your ultimate astronomical success. Early telescope users were content to perch their tubes on the ledge of a study window. It’s only been in the last century or so that site selection prior to observatory construction has really matured. In the modern era, the effects of encroaching light pollution also has to be accounted for. Telescopes have gone from backyard curiosities to behemoths of national significance.

The modern era of scopes is also traced, from the Hale and Keck telescopes to the Hubble Space Telescope, which is appropriately given its own chapter. The chapter “When Good Telescopes go Bad” is particularly illuminating, as it demonstrates the engineering challenges that seem to plague every great instrument. It’s been said that it’s never truly a great scientific or engineering breakthrough until someone has had a nervous breakdown, and building cutting edge telescopes is certainly a case in point. The author also addresses the innovative methods the have been developed to squeeze as much information as possible out of every photon of light. Just think, we can know speed, direction, composition and more just from “tasting” starlight. This was first developed by the breakthrough of spectroscopy, and further refinements such as interferometry and adaptive optics have pushed the envelope even further. adaptive optics itself used to be classified, as it was used primarily to peek at Russian payloads in low-Earth orbit. Some of this technology is truly amazing; for example, did you know it’s possible to “record” a conversation in a room just by measuring via laser the vibrations imparted on the windows? To this effect, the Oval Office actually employs “shakers” on its outer panes, probably not much different than the vibrate mode on your cell phone.

A look at the key discoveries of the telescope and some of the more bizarre and unusual telescopes is also given treatment; two of our favorite are the use of liquid metal (mercury in a precisely rotated dish!) telescopes, and of course, the Laser Interferometry Gravitational wave Observatory, a “telescope” used to hunt for gravity waves.

And that’s just the beginning. The future of telescopes will see the James Webb Space Telescope, mega observatories such as the Thirty Meter Telescope (TMT) and the 100-meter OverWhelmingly large telescope (OWL) and perhaps even more exotic arrays such as the Terrestrial Planet Finder or a large crater-based instrument on the Lunar far-side.

Do give the Telescope a look if you are thinking of buying, building, or just have a passion for these grand old instruments. Telescopes represent the cutting edge of human technology, and never fail to inspire. And as astronomers, observatories are the closest thing to a cathedral to the stars that we possess!

Astro Documentaries

Pictured is a Delta IV rocket launch from Cape Canaveral on November 21st, 2010. The image is a 20 second exposure taken at dusk, shot from about 100 miles west of the launch site. The launch placed a classified payload in orbit for the United States Air Force.

DIY Astronomy

Difficult but not impossible to catch against the dawn or dusk sky, spotting an extreme crescent moon can be a challenge. The slender crescent pictured was shot 30 minutes before sunrise when the Moon was less than 20 hours away from New. A true feat of visual athletics to catch, a good pair of binoculars or a well aimed wide field telescopic view can help with the hunt.

The Sun is our nearest star, and goes through an 11-year cycle of activity. This image was taken via a properly filtered telescope, and shows the Sun as it appeared during its last maximum peak in 2003. This was during solar cycle #23, a period during which the Sun hurled several large flares Earthward. The next solar cycle is due to peak around 2013-14.

Astronomy Gear Reviews

Located in the belt of the constellation Orion, Messier 42, also known as the Orion Nebula is one of the finest deep sky objects in the northern hemisphere sky. Just visible as a faint smudge to the naked eye on a clear dark night, the Orion Nebula is a sure star party favorite, as it shows tendrils of gas contrasted with bright stars. M42 is a large stellar nursery, a star forming region about 1,000 light years distant.

Astronomical Observing Targets

Orbiting the planet in Low Earth Orbit (LEO) every 90 minutes, many people fail to realize that you can see the International Space Station (ISS) from most of the planet on a near-weekly basis. In fact, the ISS has been known to make up to four visible passes over the same location in one night. The image pictured is from the Fourth of July, 2011 and is a 20 second exposure of a bright ISS pass.

Next to the Sun, the two brightest objects in the sky are the Moon and the planet Venus. In fact, when Venus is favorably placed next to the Moon, it might just be possible to spot the two in the daytime. Another intriguing effect known as earthshine or ashen light is also seen in the image on the night side of the Moon; this is caused by sunlight reflected back off of the Earth towards our only satellite.

A mosaic of three images taken during the total lunar eclipse of December 21st, 2010. The eclipse occurred the same day as the winter solstice. The curve and size of the Earth’s shadow is apparent in the image.